The barn and the fence are two separate devices in traditional circus. The barn is an annular ring with a width of 1.5 meters, 0.5 meter higher than the stage surface and it is usually a fixed device produced by concrete or steel structure. This kind of fixed barn can completely restrict the stage area, so the circus arena is not suitable for other forms of artistic performances. The barn also blocks the sight of part of audiences, especially the children audiences. Therefore, the entertainment field with fixed barn usually can not be applicable to other artistic forms of performances other than the circus show. Thus, the application of the circus arena is very simple and its utilization efficiency is low, difficulty to increase the benefits.
The fence is made of metal profiles for the cylindrical structure, and steel mesh or fiber woven mesh is installed fixedly outside of the cylindrical structure. The fence includes two types: integrated type and partitioned type. The integrated type fence has a large volume, and it is difficult for handling and storage, therefore, usually it is hung to the above of the stage using a winch, and when it is used, descend it to enclose the stage area. Since this fence is placed above the stage, the installation or use of other stage equipments above the stage area is restricted; of which, the lighting equipments are affected most. The partitioned type of fence needs to be assembled in the site, which is time-consuming and laborious, and if it is used in the midway of show, the performance continuity will be influenced.